Currently, future population decrease, declining birth rate, and aging population are large social problems in Japan, and local municipalities are struggling to perform optimal fiscal management, considering these problems. In order to continuously provide an administrative service of a high degree of residents' satisfaction in local municipalities in future, it is important to select optimal measures after planning these measures based on a prediction of a future population and after verifying effects when these measures are introduced.
A prediction technology of a future population is, for example, a cohort component method. A cohort is a group of people born in the same period. The cohort component method assumes future values of two “population changing components”, which are “natural growth and decline” (birth and death) and “net migration” (emigration and immigration), with respect to each cohort, and projects a future population on the basis of the assumed future values. In the cohort component method, cohorts of 5-year intervals (5-year age groups) are used, for example.
Note that a social structure projection system capable of projecting a social structure from fewer data is also considered.
See, for example, Japanese Laid-open Patent Publication No. 2003-242305.
When a population is projected by the cohort component method, population projection values of 5-year age groups are calculated for each 5-year period for example, but it is difficult to analyze a scenario in consideration of change in future birth rate, and to verify effects of introduced measures, on the basis of the population projection result. For example, in the cohort component method, the birth rate of each 5-year age group is manipulated to analyze a scenario of an improved birth rate, which makes its setting more complicated. Also, it is difficult to reflect, in the population projection, a scenario in which the birth rate improves from a year that is not at a boundary between 5-year periods. As described above, the cohort component method is not appropriate for analyzing a scenario that assumes changes in components which affect future population change.